The present invention relates to an apparatus for the rapid mixing of two fluids, particularly applicable to water treatment operations to effect the injection and "in-line" mixing of the water to be treated with reactants such as, for example, polymers, acids, bases, etc., or for carrying out more complex reactions such as coagulation.
In water treatment operations, it often is necessary to inject into the water to be treated and to mix therewith concentrated solutions of reactants, since the rate of flow of the reactants is less than the rate of flow of the water to be treated, often less than 1%.
A variety of equipment has been described in the past with which this type of in-line mixing is to be achieved, for example, injection tubes, baffle or fin systems, ejectors, etc. However, these different systems have various disadvantages. Thus, when using injection tubes or systems combining tubes and diaphragms, the blending or mixing is effected over conduits of very long length, for example lengths of from 3 to 100 times the diameter of the conduit conveying the water to be treated, this for a relatively poor degree of mixing. If fin, tube or lamella systems or an ejector are used, the quality of the mixture is good, but the mixing still takes place over a relatively long conduit length, of from 2 to 6 times the diameter of the conduit through which passes the water to be treated. Additionally, such systems result in relatively high friction or pressure losses ranging from 1 to 7 m of a column of water. Furthermore, none of the known systems permit two fluids to be mixed directly if the rate of flow of one of the fluids is much lower than the rate of flow of the other fluid, for example less than 0.01%.